1. Field of the Invention
The present invention relates to a photographing optical lens assembly, and more particularly, to a compact photographing optical lens assembly used in an electronic product.
2. Description of the Prior Art
In recent years, due to the popularity of portable electronic products with photographing functions, the demand for compact imaging lens system is increasing, and the sensor of a general photographing camera is none other than CCD (Charge-coupled Device) or CMOS device (Complementary Metal-oxide-semiconductor Device). Furthermore, as advances in semiconductor manufacturing technology have allowed the pixel size of sensors to be reduced, and the resolution of compact imaging lens system has gradually increased, there is an increasing demand for compact imaging lens system featuring better image quality.
A conventional compact imaging lens generally comprises two lens elements so as to reduce the production cost, such as the imaging lens disclosed in U.S. Pat. No. 7,525,741. As the two-element lens has limited capability to correct aberrations, it became insufficient for a high-end photographing module. However, employing excess number of lens elements will make it difficult to reduce the total track length of the lens.
To obtain good image quality and maintain a compact form, a photographing optical lens assembly comprising three lens elements is a feasible solution. The optical lens system for taking images disclosed in U.S. Pat. No. 7,436,603 is of a triplet type comprising, in order from the object side to the image side: a first lens element with positive refractive power, a second lens element with negative refractive power, and a third lens element with positive refractive power. Although the arrangement facilitates the correction of most of the aberrations caused by the optical system, it requires a longer total track length, and thus, the size of the optical lens system for taking images must increase to accommodate the lengthened total track length. Consequently, the optical lens system for taking images is unable to maintain a compact form.
Therefore, a need exists in the art for a photographing optical lens assembly that features better image quality, and maintains a moderate total track length for compact, portable electronic products.